[LTP] [PATCH] swapon01: Improving test with memory limits and swap reporting

[Li Wang]

On Sat, Jan 20, 2024 at 2:40 PM Li Wang <liwang@redhat.com> wrote:

> This is target to create a more robust and controlled environment to test
> the swapon system call. By introducing memory limits through cgroups and
> filling memory with a known pattern, the test can better assess swapon
> behavior when the system experiences memory pressure.
>
> Additionally, the reporting of "SwapCached" memory before turning off the
> swap file provides a clearer understanding of the swap system's state in
> response to the test conditions.
>
> Signed-off-by: Li Wang <liwang@redhat.com>
> ---
>  testcases/kernel/syscalls/swapon/swapon01.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
>
> diff --git a/testcases/kernel/syscalls/swapon/swapon01.c
> b/testcases/kernel/syscalls/swapon/swapon01.c
> index e1fe50459..faf4a8002 100644
> --- a/testcases/kernel/syscalls/swapon/swapon01.c
> +++ b/testcases/kernel/syscalls/swapon/swapon01.c
> @@ -20,6 +20,7 @@
>
>  #define MNTPOINT       "mntpoint"
>  #define SWAP_FILE      MNTPOINT"/swapfile01"
> +#define TESTMEM                (1UL<<30)
>
>  static void verify_swapon(void)
>  {
> @@ -29,12 +30,19 @@ static void verify_swapon(void)
>                 tst_brk(TBROK | TERRNO,
>                                 "Failed to turn off swapfile, system
> reboot recommended");
>         }
> +
> +       tst_res(TINFO, "SwapCached: %ld Kb",
> SAFE_READ_MEMINFO("SwapCached:"));
>  }
>
>  static void setup(void)
>  {
>         is_swap_supported(SWAP_FILE);
>         make_swapfile(SWAP_FILE, 0);
> +
> +       SAFE_CG_PRINTF(tst_cg, "cgroup.procs", "%d", getpid());
> +       SAFE_CG_PRINTF(tst_cg, "memory.max", "%lu", TESTMEM);
> +
> +       tst_pollute_memory(TESTMEM, 0x41);
>

Oops, this pollute memory should move to the behind of swapon,
I forget to submit the last changes when formatting the patch.

--- a/testcases/kernel/syscalls/swapon/swapon01.c
+++ b/testcases/kernel/syscalls/swapon/swapon01.c
@@ -26,12 +26,13 @@ static void verify_swapon(void)
 {
        TST_EXP_PASS(tst_syscall(__NR_swapon, SWAP_FILE, 0));

+       tst_pollute_memory(TESTMEM, 0x41);
+       tst_res(TINFO, "SwapCached: %ld Kb",
SAFE_READ_MEMINFO("SwapCached:"));
+
        if (TST_PASS && tst_syscall(__NR_swapoff, SWAP_FILE) != 0) {
                tst_brk(TBROK | TERRNO,
                                "Failed to turn off swapfile, system reboot
recommended");
        }
-
-       tst_res(TINFO, "SwapCached: %ld Kb",
SAFE_READ_MEMINFO("SwapCached:"));
 }

 static void setup(void)
@@ -41,8 +42,6 @@ static void setup(void)

        SAFE_CG_PRINTF(tst_cg, "cgroup.procs", "%d", getpid());
        SAFE_CG_PRINTF(tst_cg, "memory.max", "%lu", TESTMEM);
-
-       tst_pollute_memory(TESTMEM, 0x41);
 }

 static struct tst_test test = {


-- 
Regards,
Li Wang